7. TEST CERTIFICATE & WARRANTY................................................................................ 23
Warning statements identify condition or practices that could result in
injury or loss of life.
SAFETY TERMS AND SYMBOLS
These terms may appear in this manual or on the product :
Caution statements identify conditions or practices that could result in
damage to this product or other property.
The following symbols may appear in this manual or on the product :
!ATTENTION
refer to Manual
Protective
Conductor
Terminal
Earth (ground)
Terminal
WARNING.
CAUTION.
!
!
DANGER
High Voltage
CE Declaration of Conformity
EN50081-2 : Electromagnetic compatibility-
(1992) Generic emission standard
Part 1 : Residential, commercial and light industry
We
KUSAM ELECTRICAL INDUSTRIES LTD.
G-17, Bharat Industrial Estate, T. J. Road, Sewree (W),
Mumbai- 400 015. (INDIA).
Declare under sole responsibility that the below mentioned products Model KM -20-20:20MHz
Oscilloscope with Frequency meets the intent of Directive 89/336/EEC;
92/31/EEC; 93/68/EEC for Electromagnetic Compatibility. Compliance was demonstrated to the
following specifications as listed in the industrial Technology Research institute :
EN50082-2 : Electromagnetic compatibility-
(1992) Generic emission standard
Part 1 : Residential, commercial and light industry
Conducted Emission
Radiated Emission
EN 55022 class B(1994)
EN 55011 class B(1991)
Current Harmonics EN 61000-3-2
Voltage Fluctuations EN 61000-3-3
Low Voltage Directive EN 61010-1
(1995)
(1995)
(1993)
Electrostatic Discharge
Radiated Immunity
Electrical Fast Transients
Surge immunity
Voltage Dip / Interruption
IEC 1000-4-2
IEC 1000-4-3
IEC 1000-4-4
IEC 1000-4-5
EN 61000-4-11
(1995)
(1995)
(1995)
(1995)
(1994)
1. GENERAL
1.1 Description
The KM-20 family oscilloscope are dual-channel oscilloscope with maximum sensitivity of 1mV / DIV.
The time base provides a maximum sweep time of 0.2 mS / DIV. When magnified by 10, the sweep
speed is 20ns / DIV. Each of these oscilloscope employs a 6-inch rectangular type cathode-ray tube
with red internal graticule.
These oscilloscopes are sturdy, easy to operate and exhibits high operational reliability.
1.2 Features
1) High intensity CRT with high acceleration voltage :
The CRT is a high beam transmission, high intensity type with a high acceleration voltage of 2KV. For
KM-20-10-20MHz and KM-20-20:20MHz. It displays clear readable traces even at high sweep speeds.
2) A trigger level lock function which makes the triggering adjustment unnecessary.
3) Alternate triggering :
Even an observation of two waveforms of different frequencies, the waveform of the each channel is
stably triggered.
4) TV sync triggering :
The oscilloscope has a sync separator circuit for triggering of TV-V and TV-H signals.
5) CH1 Output :
Terminated 50 W output of channel 1 signal available on rear panel for driving frequency counter or other
instruments.
6) Z-Axis Input :
Intensity modulation capability permits time or frequency markers to be added. Trace blank with positive
signal, TTL compatible.
7) X-Y operation :
Set the switch to X-Y. Then the instrument works as an X-Y oscilloscope. CH1 can be applied as
horizontal deflection (X-axis) while CH2 provide vertical deflection (Y-axis).
1
2. TECHNICAL SPECIFICATIONS
MODELSPECIFICATIONS
20MHz OSCILLOSCOPE
KM-20-10 : 20MHz / KM-20-20 : 20MHz
5mV~5V/DIV, 10 steps in 1-2-5 sequence
£ £ 3% (x5 MAG 5%)
To 1/2.5 or less of panel-indicated value.
DS-20MHz (x5 MAG:DC ~ 7MHz)
AC coupling : Low limit frequency 10Hz. (With reference to 100KHz,
8DIV, Frequency response with-3dB.)
Approx. 17.5ns (x5 MAG:Approx. 50nS)
Approx. 1M ohm // Approx. 25pF
Overshoot : 5% (At 10mV/DIV range)£
Other distortions and other ranges : 5% added to the above value.
Adjustable on panel.
<± 0.1 DIV of amplitude change when waveform of 2 DIV at graticule center is moved vertically.
CH1 : CH1 single channel.
CH2 : CH2 single channel.
DUAL : CH1 and CH2 are displayed. ALT or CHOP selectable at any sweep rate.
ADD : CH1 + CH2 algebraic addition.
Approx. 250 KHz
AC, GND, DC
300V peak (AC : frequency 1KHz or lower).
When set probe switch at 1:1, the maximum effective readout is 40Vpp (14Vrms at sine wave).
or set probe switch at 10:1, the maximum effective readout is 400Vpp (140Vrms at sine wave).
50:1 or better at 50KHz sinusoidal wave.(When sensitivities of CH1 and CH2 are set equally)
>1000:1 at 50KHz
> 30:1 at 20 MHz
At least 20 mV / DIV into a 50 ohm termination. Bandwidth is 50Hz to at least 5MHz.
Balanced point variation : 1 DIV (Reference at center graticule.)£
VE
RT
ICA
L A
XIS
Sensitivity
Sensitivity accuracy
Vernier vertical sensitivity
Frequency bandwidth
Rise time
Input impedance
Square wave characteristics
DC balance shift
Linearity
Vertical modes
Chopping repetition frequency
Input coupling
Maximum Input voltage
Common mode rejection ratio
Isolation between channels (At 5mV / DIV range)
CH1 signal output
CH2 INV BAL.
2
MODELSPECIFICATIONS
20MHz OSCILLOSCOPE
KM-20-10 : 20MHz / KM-20-20 : 20MHz
Triggering source
AC:20Hz to full bandwidth
+/-
20Hz~2MHz; 1.0 DIV, TRIG-ALT:2 DIV, EXT:200mV
2MHz~20MHz: 1.5DIV
TRIG-ALT:3 DIV,EXT: 800mV
TV : Sync pulse more than 1 div (EXT:1V)
AUTO :Sweeps run in the free mode when no triggering input signal is applied. (Applicable for rapetitive signals of frequency 25 Hz or over).NORM : When no triggering signal is applied, the trace is in the ready state and not displayed.TV-V : This setting is used when observing the entire vertical picture of television signal.TV-H : This setting is used when observing the entire horizontal picture of television signal. (Both TV-V and TV-H synchronize only when the synchronizing signal is negative)
Approx. 1M ohm//approx. 25pF
300V(DC+AC peak), AC : Frequency not higher than 1KHz
0.2 mSec~0.5Sec/DIV, 20steps in 1-2-5 sequence
10 times
± 5% (20nSec~50nSec are uncalibrated)
±3%,x10MAG : ±5%(20ns and 50ns are uncalibrated)
Within 2 DIV.at CRT screen center
Same as vertical axis.(X-axis CH1 input signal; Y-axis : CH2 input signal)
DC to at least 500KHz
£ o3 at DC~50KHz
Coupling
Slope
Sensitivity
Triggering modes
EXT triggering signal input Input impedanceMax.input voltage
Sweep time
Sweep time accuracy
Vernier sweep time control
Sweep magnification
X10MAG sweep time accuracy
Linearity
Position shift caused by x10MAG
Sensitivity
Frequency bandwidth
± 3%
£ 1/2.5 of panel-indicated value
X - Y phase difference
CH1, CH2, LINE, EXT (CH1 AND CH2 can be selected only when the vertical mode is DUAL or ADD.In ALT mode, if the TRIG ALT switch is pushed in, it can be use for alternate triggering of two different source.
TRIGGERING
HORIZIONAL
AXIS
X-Y MODE
3
MODELSPECIFICATIONS
20MHz OSCILLOSCOPE
KM-20-10 : 20MHz / KM-20-20 : 20MHz
Sensitivity
DC~2MHz
Approx. 47K ohm
30V (DC+AC peak, AC frequency 1KHz)£
Positive-going square wave
Frequency bandwidth
Input resistance
Maximum input voltage
Waveform
5Vp-p(Positive-going signal decreases intensity)
CRT
Frequency
Duty ratio
Output voltage
Output impedance
Type
Phosphor
Acceieration voltage
Effective screen size
Graticule
Trace rotation
CALIBRATIONVOLTAGE
Z AXIS
Approx. 1KHz
Within 48:522Vp-p ±2%
Approx. 1K ohm.
6-inch rectangular type, internal graticule
P31
Approx. 2KV
Provided
DIV(1 DIV=10mm(0.39in))
Internal
Line Power RequirementsVoltage : AC 110V/220V ±10% selectableFrequency : 50Hz or 60HzPower consumption : Approx. 40VA, 35W(max.)
Operating Environment AccessoriesIndoor use Power cord......................1Altitude up to 2000 m Instruction manual...........1Ambient temperature: Probes.............................2
o o o oTo satisfy specifications: 10 to 35 C(50 to 95 F)o o o oMaximum operating ranges: 0 to40 C(32 to104 F)
Relative humidity: 85%RH(max.) Non condensingInstallation Category IIPollution degree 2
Mechanical Specifications Storage Temperature & Humidity
o oDimensions : 310W x 150H x 455D (mm) -10 to 70 C, 70%RH (maximum)Weight : Approx. 8Kg.
4
3.1 Unpacking the Oscilloscope
The oscilloscope is shipped from the factory after being fully inspected and tested. Upon receiving the instrument, immediately unpack and inspect it for any damages that might have been sustained during transportation. If any sign of damage is found, immediately notify the bearer and / or the dealer.
3.2 Checking the Line voltage
These oscilloscopes will operate on AC 220V or 110V setted by factory. Before connecting the power plug to an AC line outlet, makes sure the voltage selector is set to the correct position corresponding to the line voltage. Note the oscilloscope may be damaged if it is connected to the wrong AC line voltage.
3. PRECAUTIONS BEFORE OPERATING THE OSCILLOSCOPE
WARNING. To avoid electrical shock the power cord protective
grounding conductor must be connected to ground.
Replace the required fuses shown below.
Line voltage Range Fuse
T 0.5A
250V198 ~ 242AC 220V
T 1.0A
250V109 ~ 121AC 110V
WARNING. To avoid personal injury, disconnect the power cord
before removing the fuse holder.
5
!
!
3.3 Environmento o o oThe normal ambient temperature range of this instrument is 0 to 40 C (32 to 104 F). Operation of
the instrument above this temperature range may cause damage to the circuits.Do not use the instrument in a place where strong magnetic or electric field exists, such fields may disturb the measurement.
3.4 Equipment Installation, and OperationEnsure there is proper ventilation for the hole vents in the oscilloscope case.If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.
3.5 CRT IntensityTo prevent permanent damage to the CRT phosphor, do not make the CRT trace excessively bright or leave the spot stationary for an unreasonably long time.
3.6 Withstanding Voltages of Input TerminalsThe withstanding voltages of the instrument input terminals and probe input terminals are as shown in the following table. Do not apply voltages higher than these limits, when set probe switch at 1:1, the maximum effective readout is 40Vpp (14 Vrms at sine wave). When set probe switch at 10:1, the maximum effective readout is 400Vpp (140Vrms at sine wave).
CH1, CH2, inputs
EXT TRLG IN input
Probe inputs
Z AXIS input
Maximum input voltage CAUTION. To avoid instrument
damage, do not exceed maximuminput voltages.Maximum input voltages must havefrequencies less than 1 KHz.
!Input terminal
300V peak
300V peak
600V peak
30V peak
If an AC voltage which is superimposed on a DC voltage is applied, the maximum peak value of CH1 and CH2 input voltages must not exceed + or - 300V. So for AC voltages with a mean value of zero volt the maximum peak value is 600Vpp.
6
Figure 4-1MODEL KM 20-20 : 20MHz
52
1+
+
+
50
20
10
5
++
+
+
+
+ 5
2
1
2
5
10
2050
1251
2
TIME/DIV
10UNCAL
VERTICAL
CAL
X10 MAG
SWP, VARPOSITION
8.8.8.8.8.8 KHz
HORIZONTAL TRIGGER
TRIG. ALT
AUTO
TV-V
NORM
TV-H
MODE
LINE
EXT
CH1
CH2
SOURCE
TRIG IN
SLOPELEVEL 1MW//pF
LOCK CAT II300VPKMAX.
!
2
5
1
1
5
5
10
20
502
VOLTS / DIV
POSITION DC
BAL
DC
BAL
CAL
PULLX5MAG
CH11MW//25pF
VOLTS / DIV
POSITION
DUAL
ADD
CH1
CH2
CH2 INV
AC
GND
DC
AC
GND
DC
ALTCHOP
MODE
X
CAT II300VpK MAX.
!
5
10
mV
5
2
1
5
2 1
50
20
VAR
L
CH2
CAT II300VpK MAX.
!
1MW//25pF
Y
PULL+5MAG
CAL
32 39 31 31 29 28 27 29 25 24 23
40
2221201918171615141312111098765
mS
mS
V
mV
VAR
KM-20-20 : 20MHz
X-Y
4321
OSCILLOSCOPE
7
Figure 4-1MODEL KM-20-10:20MHz
8
!
Z-AXIS INPUT
CAT II 30VpK MAX.
! CH1 OUTPUT
20mV/DIV INTO 50W
FUSE~AC
ENSURE THE POWER IS REMOVED FROMTHE INSTRUMENT BEFORE REPLACING THE FUSE
!
POWER MAX. 35 WATTS, 40VA ! WARNING
TO AVOID ELECTRIC SHOCK THE POWER CORD
PROTECTIVE GROUNDING CONDUCTOR MUST BE
CONNECTED TO GROUND.
FOR CONTINUED THE PROTECTION REPLACE ONLY
WITH SPECIFIED TYPE AND RATED FUSE.
NO OPERATOR SERVICEABLE COMPONENTS INSIDE
DO NOT REMOVE COVERS. REFER SERVICING TO
QUALIFIED PERSONNEL.
LINE VOLTAGESELECTING
RANGE(50/60Hz)
FUSE
220V
110V
198-242
109-121T 0.69A
250V
T 0.315A250V
383736
41
3534 CRT :
POWER.........................(6)
Main power switch of the instrument. When this switch is turned on, the LED(5) is also turned on.
INTEN...........................(2)
Controls the brightness of the spot or trace.
FOCUS.........................(3)
For focusing the trace to the sharpest image.
TRACE ROTATION...........(4)
Semi-fixed potentiometer for aliging the horizontal trace in parallel with graticule lines.
FILTER.............................(33)
Filter for ease of waveform viewing.
Vertical Axis.
CH1 (X) Input..................(8)
Vertical input terminal of Ch1. When in X-Y operation, X-axis input terminal.
CH2 (Y) Input ................(20)
Vertical input terminal of Ch2. When in X-Y operation, Y-axis input terminal.
AC-GND-DC...................(10) (18)
Switch for selecting connection mode between input signal and vertical amplifier.
AC : AC coupling
GND : Vertical amplifier input is grounded and input terminals are disconnected.
DC : DC coupling
VOLTS / DIV................(7) (22)
Select the vertical axis sensitivity, from 5mV / DIV to 5V / DIV in 10 ranges.
4.OPERATION METHOD
4.1Introduction of Front Panel
9
VARIABLE..................(9) (21)Fine adjustment of sensitivity, with a factor of 1/2.5 of the indicated value. When in the CAL position, sensitivity is calibrated to indicated value. When this knob is pulled out (x5 MAG state), the amplifier sensitivity is multiplied by 5.
CH1 & CH2 DC BAL. (13) (17)These are used for the attenuator balance adjustment. See page 20 DC BAL adjustments for the details.
POSITION................(11) (19)Vertical positioning control of trace or spot.
VERT MODE.....................(14)Select operation modes of CH1 and CH2 amplifiers.CH1 : The oscilloscope operates as a single-channel instrument with CH1 alone.CH2 : The oscilloscope operates as a single-channel instrument with CH2 alone.DUAL : The oscilloscope operates as a dual-channel instrument both CH1 and CH2.ADD : The oscilloscope displays the algebraic sum (CH1 + CH2) or difference (CH1 - CH2) of
the two signals. The pushed in state of CH2 INV(16) button is for the difference (CH1-CH2).
ALT / CHOP...................(12)When this switch is released in the dual-trace mode, the channel 1 & channel 2 inputs are
Alternately displayed (normally used at faster sweep speeds).When this switch is engaged in the dual-trace mode, the channel 1 and channel 2 inputs are chopped and displayed simultaneously (normally used at slower sweep speeds).
CH2 INV.........................(16)Inverts the CH2 input signal when the CH2 INV switch mode is pushed in the channel 2 input signal in ADD mode and the channel 2 trigger signal pickoff are also inverted.
Triggering :EXT TRIG IN input terminal..............(24)
Input terminal is used for external triggering signal. To use this terminal, set SOURCE switch(23) to the EXT position.
10
SOURCE....................(32)
Select the internal triggering source signal, and the EXT TRIG IN input signal.
CH1 : When the VERT MODE switch (14) is set in the DUAL or ADD state, select CH1 for the internal
triggering source signal.
CH2 : When the VERT MODE switch (14) is set in the DUAL or ADD state, select CH2 for the internal
triggering source signal.
TRIG.ALT(27) : When the VERT MODE switch (14) is set in the DUAL or ADD state, and the SOURCE
switch(23) is selected at CH1 or CH2, with the engagement of the TRIG.ALT switch (27), it will
alternately select CH1 & CH2 for the internal triggering source signal.
LINE : To select the AC powerline frequency signal as the triggering signal.
EXT : The external signal applied trough EXT TRIG IN input terminal (24) is used for the external
triggering source signal.
SLOPE....................(26)
Select the triggering slope.
“+” : Triggering occurs when the triggering signal crosses the triggering level in positive-going direction.
“-” : Triggering occurs when the triggering signal crosses the triggering level in negative-going direction.
LEVEL......................(28)
To display a synchronized stationary waveform and set a start point for the waveform.
Toward: “+” : The triggering level moves upward on the display waveform.
Toward: “-” : The triggering level moves downward on the display waveform.
LOCK........................(40)
Click(28) by fully clockwise position, then triggering level is automatically maintained at optimum value
irrespective of the signal amplitude, requring no manual adjustment of triggring level.
TRIGGER MODE..............(25)
Select the desired trigger mode.
AUTO : When no triggering signal is applied or when triggering signal frequency is less than 25Hz,
sweep runs in the free run mode.
NORM : When no triggering signal is applied, sweep is in a ready state and the trace is blanked out.
Used primarily for observation of signal 25Hz.
TV-V : This setting is used when observing the entire vertial picture of television signal.
£
11
TV-H : This setting is used when observing the entire horizontal picture of television signal.
(Both TV-V and TV-H synchronize only when the synchronizing signal is negative.)
Time Base
TIME / DIV.................(29)
Sweep time ranges are available in 20 steps from 0.2 ms / div to 0.5 S/div.
X-Y : This position is used when using the instrument as an X-Y oscilloscope.
SWP.VAR..................(30)
Vernier control of sweep time. This control works as CAL and the sweep time is calibrated to the value
indicated by TIME / DIV of sweep can be varied continuously when shaft is out of CAL position. Then the control
is rotated in the direction of arrow to the full, the CAL state is produced and the sweep time is calibrated to the
value indicated by TIME / DIV. Counterclockwise rotation to the full delays the sweep by 2.5 time or more.
POSITION.............(32)
Horizontal positioning control of the trace or spot.
X10 MAG...................(31)
When the button is pushed in, a magnification of 10 occurs.
Others
CAL......................(1)
This terminal delivers the calibration voltage of 2 Vp-p, 1KHz, positive square wave.
GND.....................(15)
Ground terminal of oscilloscope mainframe.
FREQUENCY METER........(39) (KM 20-20 : 20MHz) Display a synchronized signal frequency
4.2 Introduction of Rear Panel
Z AXIS INPUT..............(34)
Input terminal for external intensity modulation signal.
CH1 SIGNAL OUTPUT..........(35)
Delivers the CH1 signal with a voltage of approximately 20mV per 1 DIV into a 50-ohm termination.
Suitable for frequency counting, etc.
12
AC POWER Input Circuit AC Power input connector.........................(36) AC Power input socket. Connect the AC power cord (supplied) to this connector. FUSE........................................................(37) Fuse rating is shown in Page 5. Studs........................................................(38) Studs for laying the oscilloscope on its back to operate it in the upward posture. Also used to take up the power cord. LINE VOLTAGE SELECTOR...................(41) To select power sources
4.3 Basic Operation -- Single-channel Operation
Setting
Before connecting the power cord to an AC line outlet, make sure that the voltage input on the rear panelof the instrument is correctly set for the AC line voltage. After ensuring the voltage setting, set the switches and controls of the instrument as shown below.
Disengage position (OFF)
Mid-position
Mid-position
CH1
Released (ALT)
Released
Mid-position
0.5V / DIV
CAL(clockwise position)
GND
CH1
Item No Setting
SLOPE
TRIG. ALT
TRIGGER MODE
TIME / DIV
SWP.VER
POSITION
x10 MAG
LEVEL
(26)
(27)
(25)
(29)
(30)
(32)
(31)
(28)
+
Released
AUTO
0.5mSec/DIV
CAL position
Mid-position
Released
Locked
13
Item No
POWER
INTEN
FOCUS
VERT MODE
ALT/CHOP
Ch2 INV
POSITION
VOLTS / DIV
VARIABLE
AC-GND-DC
SOURCE
(6)
(2)
(3)
(14)
(12)
(16)
(11) (19)
(7) (22)
(9) (21)
(10) (18)
(23)
After setting the switches and controls as mentioned, connect the power cord to the AC line outlet, and then continue as follows :
1) Engage the POWER switch and make sure that the power led is turned on. In about 20 seconds, a trace will appear on the CRT screen. If no trace appears in about 60 seconds, counter check the switch and control setting.
2) Adjust the trace to an appropriate brightness and Image with the INTEN control and FOCUS control respectively.
3) Align the trace with the horizontal centre line of the graticule by adjusting the CH1 POSITION control and TRACE ROTATION control (adjustable by screwdriver).
4) Connect the probe to the CH1 INPUT terminal and apply the 2Vp-p CALIBRATOR signal to the probe tip.
5) Set the AC-GND-DC switch to the AC state. A waveform as shown in the figure 4-3 will be displayed on the CRT screen
6) Adjust the FOCUS control so that the trace image appears sharply.7) For signal viewing, set the VOLTS / DIV switch and TIME / DIV switch
in appropriate positions so that signal waveform is displayed clearly.
8) Adjust the POSITION and POSITION controls in appropriate positions so that the displayed waveform is aligned with the graticule and voltage(Vp-p) and period(T) can be read conveniently.The above are the basic operating procedures of the oscilloscope. The above procedures, are for single-channel operation with CH1. Single-channel operation with CH2 can also be achieved in a similar manner. Further operation methods are explained in the subsequent paragraph.
??
4.4 Dual-channel OperationChange the VERT MODE switch to the DUAL states so that
trace(CH2) is also displayed (The explanation in the proceeding section is of CH1). At this state of procedure, the CH1 trace is the square wave of the clibrator signal and the CH2 trace is a straight line since no signal is applied to this channel yet.
Now, apply the calibrator signal to the vertical input terminal of CH2 with the probe as is the case for CH1. Set the AC-GND-DC switch to the AC state. Adjust vertical POSITION knobs(11) and (19) so that both channel signals are displayed as shown in Figure 4-4.
14
Figure 4-3
Figure 4-4
Signal of CH1
Signal of CH2
When ALT / CHOP switch is released (ALT MODE), the input signals applied respectively to CH1 and CH2 appears on the screen alternatively at each sweep. This setting is used when the sweep time is short in 2-channel observation.
When ALT / CHOP switch is engaged (CHOP MODE), the input signals applied to CH1 and CH2 are switched at about 250KHz independent of the sweep and at the same time appear on the screen. This setting is used when the sweep time is long in 2-channel observation.
When in the dual channel operation (DUAL or ADD mode), the CH1 or CH2 signal must be selected for the triggering source signal by means of the SOURCE switch. If both CH1 and CH2 signals are in a synchronized relationship, both waveforms can be displayed stationary; if not, only the signal selected by the SOURCE switch can be stationary. If the TRIG.ALT push switch is engaged, both waveforms can be displayed stationary.
4.5 ADD Operation
An algebraic sum of the CH1 and CH2 signals can be displayed on the screen by setting the VERT MODE switch to the ADD state. The displayed signal is the difference between CH1 and CH2 signals if the CH2 INV push switch is engaged.
For accurate addition or subtraction, it is a prerequisite that the sensitivities of the two channels are adjusted accurately at the same value by means of the VARIABLE knobs. Vertical positioning can be made with the POSITION knob of either channel. In view of the linearity of the vertical amplifiers, it is most advantage to set both knobs in their mid-positions.
4.6 Triggering
Proper triggering is essential for efficient operation of an oscilloscope. The user must be thoroughly familiar with the triggering functions and procedures.
(1) Functions of MODE switch:
AUTO : When the AUTO switch is engaged, automatic sweep operation is selected in automatic sweep operation, the sweep generator free runs to generate a sweep without a trigger signal. However, it automatically switches to triggered sweep operation if an acceptable trigger source signal is present. The AUTO position is handy when first setting up the scope to observe a waveform; it provides sweep for waveform observation until other controls can properly set. Once the controls are set, operation is often switched back to the NORM triggering mode, since it is more sensitive. Automatic sweep must be used for DC measurements and signals of such low amplitude that they will not trigger the sweep.
NORM : The NORM switch provides normal triggered sweep operation. The sweep remains at rest until the selected trigger source signal crosses the threshold level set by the TRIG LEVEL control. The trigger causes one sweep to be generated, after whcih the sweep again remains at rest until triggered. In the NORM position, there will be no trace unless an adequate trigger signal is present. In the ALT mode of dual trace operation with NORM sweep selected, there will be trace unless both channel 1 and 2 signals are adequate for triggering.
15
TV-V : Setting the MODE switch to the TV-V position permits selection of vertical sync pulses for sweep
triggering when viewing composite video waveforms. Vertical sync pulses are selected as trigger
to permit viewing of vertical fields and frames of video. A sweep time of 2 ms/div is appropriate for
viewing fields of video and 5 ms/div for complete frames (two interlaced fields) of video.
TV-H : Setting the MODE switch to the TV-H position permits selection of horizontal sync pulses for sweep
triggering when viewing composite video waveforms. Horizontal sync pulse are selected as trigger
to permit viewing of horizontal fields of video. A sweep time of about 10ms / div is appropriate for
displaying lines of video. The SWP VAR control can be set to display the exact number of
waveforms desired.
This oscilloscope synchronizes with only (-) polarity, that is, the sync pulses are negative and the
video is positive as shown in Figure 4-5.
The displayed signal itself or a trigger signal which has a time
relationship with the displayed signal is required to be applied to the
trigger circuit to display a stationary signal on the CRT screen.
The SOURCE switch is used for selecting such a triggering source.
CH1 : The internal trigger method which is used most commonly.
CH2 : The signal applied to the vertical input terminal is branched off from the preamplifier and is fed to
the trigger circuit through the VERT MODE switch. Since the triggering signal is the measured
signal itself, a stable waveform can be readily displayed on the CRT screen. When in the DUAL or
ADD operation, the signal selected by the SOURCE switch is used as the triggering source signal.
Line : The AC power line frequency signal is used as the triggering signal. This method is effective when
the measured signal has a relationship with the AC line frequency, especially for measurement of
low level AC noise of audio equipment, thyristor circuits, etc.
EXT : The sweep is triggered with an external signal applied to the external trigger input terminal. An
external signal which has a periodic relationship with respect to the measured signal is used.
Since the measured signal is not used as the triggering signal, the waveforms can be displayed
more independent than the measured signal.
(2) Functions of SOURCE switch :
Figure 4-5
16
(3) Functions of TRIG LEVEL control and SLOPE switch :
A sweep trigger is developed when the trigger source signal crosses a preset threshold level. Rotation of the TRIG LEVEL control varies the threshold level. In the + direction, the triggering threshold shifts to a more positive value, and in the-direction, the triggering threshold shifts to a more negative value. When the control is centered, the threshold level is set at the approximate average of the signal used as the triggering source.
The TRIG LEVEL control adjusts the start of the sweep to almost any desired point on a waveform. On sine wave signals, the phase at which sweep begins is variable. Note that if the TRIG LEVEL control is rotated toward its extreme + or - setting, no sweep will be developed in the NORM trigger mode because the triggering threshold exceeds the peak amplitude of the sync signal.
When the TRIG SLOPE switch is set to the (+) position (up), the sweep is developed from the trigger source waveform as it crosses the threshold level in a positive-going direction. When the TRIG SLOPE control is set to the (-) position (down), a sweep trigger is developed from the trigger source waveform as it crosses the threshold level in a negative-going direction. This switch selects the slope(polarity) triggering signal as shown in Figure 4-6.
LEVEL LOCK
Control level(28) to fally clockwise the triggring level is locked at a fixed value, and stable triggering is made without requring level adjustment.
This automatic level lock function is effective when the singal amplitude on the screen or the input voltage of the external triggering signal is with in the following vauge :
KM-20-10 : 20MHz / KM-20-20 : 20MHz
50Hz - 5MHz : 1.0 DIV
5MHz -- 20MHz : 1.5 DIV
³
³
(4) Function of TRIG ALT switch :
The TRIG ALT switch is used to select alternate triggering and alternate display when the DUAL-trace VERT
MODE is selected (the switch has on effect in the CH1, CH2, or ADD modes). In the alternate triggering mode
(when dual-trace operation is selected), the trigger source alternates between channel 1 and channel 2 with each
sweep. This is convenient for checking amplitudes, waveshape, or waveform period measurements, and even
permits simultaneous observation of two waveforms which are not related in frequency or
Slope “-” Range
Slope “+” Range
Figure 4-6 Level+
-
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4.9 X - Y Operation
Set the TIME / DIV switch to X - Y position.
Then the instrument works as an X-Y oscilloscope.
Each input is applied to the instrument as follows.
X-axis signal (horizontal axis signal ); Ch1 INPUT.
Y-axis signal (vertical axis signal ) : Ch2 INPUT.
Note : When high frequency signals are displayed in the X-Y
operation, pay attention to the frequency bandwidths and
phase difference between X and Y-axis.
X - Y Operation permits the oscilloscope to perform many measurements not possible with conventional sweep
operation. The CRT display becomes an electronic graph of two instantaneous voltages. The display may be a
direct comparison of the two voltages such as a vectorscope display of video color bar patterns. However, the X-Y
mode can be used to graph almost any dynamic characteristic if a transducer is used to change the characteristic
(frequency, temperature, velocity, etc.) Into a voltage. One common application is frequency response
measurements, where the Y-axis corresponds to signal amplitude and the X-axis corresponds to frequency.
1. Set the TIME / DIV control to the X-Y position (fully counterclockwise). In this mode, channel 1 becomes
the X-axis input and channel 2 becomes the Y-axis input.
2. The X and Y positions are now adjusted using the horizontal POSITION and CH2 POSITION
controls respectively.
3. Adjust the amount of vertical (Y-axis) deflection with the CH2 VOLTS / DIV and VAR controls.
4. Adjust the amount of horizontal (X-axis) deflection with the CH1 VOLTS / DIV and VAR controls.
??
Y axis (CH2)
X axis (CH1)
Figure 4-8
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period. However thmeasurements, both traces must be triggered by the same sync signal.
When the CHOP and the TRIG ALT switches are both engaged during dual-trace operation,
synchronization of the display is not possible because the chopping signal becomes the trigger. Use
the ALT mode by itself, or select CH1 or CH2 as trigger source.
is setting is not suitable for phase or timing comparison measurements. For such
4.7 TIME / DIV Control
Set the TIME/DIV control to display the desired number of cycles of the waveform. If there are too many
cycles displayed for good resolution, switch to a faster sweep speed. If only a line is displayed, try a slower
sweep speed. When the sweep speed is faster than the waveform being observed, only part of it will be
displayed. Which may appear as a straight line for a square wave or pulse waveform.
4.8 Sweep Magnification
When a certain part of the displayed waveform is needed to
be expanded timewise, a faster sweep speed may be used.
However, if the required portion is apart from the starting point of
the sweep, the required portion may run off the CRT screen. In
such a case, push in the x10 MAG button.
When this has been done, the displayed waveform will be
expanded 10 times to the right and left with the center of screen
as the center of expansion.
The sweep time during the magnification operation is as
follows :
(Value indicated by TIME/DIV switch) x 1/10
Thus, the unmagnified maximum sweep speed (1mSec / DIV)
can be increased with the magnification as follows :
1mSec / DIV x 1/10 = 100nSec / DIV
Any part can be coverd bymeans or POSITION control
Figure 4-7
10xmagnification
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4.10 Calibration of Probe
As explained previously, the probe makes up a wide range attenuator. Unless phase compensation is
properly done, the displayed waveform is distorted causing measurement errors. Therefore, the probe must
be properly compensated before use.
Connect the 10:1 probe BNC to the INPUT terminal of CH1 or CH2 and set VOLTS / DIV switch at 50mV.
Connect the probe tip to the calibration voltage output terminal and adjust the compensation trimmer on
probe for optimum square wave (minimum overshoot, rounding off and tilt).
4.11 DC BAL Adjustments
The ATT balance of the vertical axis can be made easily.
(1) Set the input couping switches of CH1 and CH2 to GND and set the TRIG MODE to AUTO. Then position the base line to the center.
(2) Turn the VOLTS / DIV switch to 5mV-10mV and adjust so that the line does not move.
Figure 4-9
(a) Correct compensation (b) Over compensation (c) Insufficient compensation
20
The following Instructions are for use by qualified person only. To avoid electrical shock, do not
perform any servicing other than in the operating instructions unless your are qualified to do so.
5.1 Fuse Replacement
If the fuse blows, the power lamp indicators will not light and the oscilloscope will not operate. The
fuse should not normally open unless a problem has developed in the unit. Try to determine and
correct the cause of the blown fuse.
Then replace only with a fuse of the correct rating and type (see page 4)
The fuse is located on the rear panel (see fig. 4-2).
5.2 Cleaning
To clean the oscilloscope, use a soft cloth dampened in a solution of mild detergent and water. Do not
spray cleaner directly on to the oscilloscope because it may leak into the cabinet and cause damage.
Do not use chemicals containing benzine, benzene, toluene, xylene, acetone, or similar solvents.
Do not use abrasive cleaners on any portion of the oscilloscope.
21
For continued fire protection disconnect power cord before replacing fuse.
Replace fuse only with 250V fuse of the specified type and rating.
WARNING
WARNING
!
5.MAINTENANCE
CH1(x)INPUT
CH1 ATTCH1
PREAMP
CH1 SIGNALOUTPUT
CH1 TRIG(X-AXIS)PICKUP AMP
CH2(Y)INPUT
CH2 ATTCH2
PREAMP
CH2TRIG PICKUP AMP
TRIGSIGNAL
TRIG SWITCH
SWITCHINGLOGIC
VERTICALMODE SWITCH
VERTSIGNAL
VERTICALOUTPUT AMP
Z-AXISAMP
Z-AXISINPUT
CRT CIRCUIT
H.V.SUPPLY
- H.V.
CH1
CH2
EXT
LINE
LINE TRIG
TRIGGER INPUTAMP
TRIGGER INPUTGENERATOR
AUTO CIRCUIT
(A)SWEEPGENERATOR
FREE RUNSIGNAL
TO EACHBLOCK
2Vp-p/1KHzSQUARE-WAVE
HORIZONTALSWITCHING
HORIZONTALOUTPUT AMP
POWER SUPPLY
CALIBRATOR
AC LINE50/60Hz
6. BLOCK DIAGRAM
22
Each “KUSAM-MECO” product is warranted to be free from defects in material and workmanship under normal use & service.
The warranty period is one year (12 months) and begins from the date of despatch of goods. In case any defect occurs in
functioning of the instrument, under proper use, within the warranty period, the same will be rectified by us free of charges,
provided the to and fro freight charges are borne by you.
This warranty extends only to the original buyer or end-user customer of a “KUSAM-MECO” authorized dealer.
This warranty does not apply for damaged Ic’s, burnt PCB’s, fuses, disposable batteries, carrying case, test leads, or to any
product which in “KUSAM-MECO’s” opinion, has been misused, altered, neglected, contaminated or damaged by accident or
abnormal conditions of operation or handling.
“KUSAM-MECO” authorized dealer shall extend this warranty on new and unused products to end-user customers only but have
no authority to extend a greater or different warranty on behalf of “KUSAM-MECO”.
“KUSAM-MECO’s” warranty obligation is limited, at option, free of charge repair, or replacement of a defective product which is
returned to a “KUSAM-MECO” authorized service center within the warranty period.
THIS WARRANTY IS BUYER’S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. “KUSAM-MECO” SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
CONSEQUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE WHATSOEVER.
All transaction are subject to Mumbai Jurisdiction.
WARRANTY
TEST CERTIFICATE
Dual Trace Oscilloscope
This Test Certificate warrantees that the product has been inspected and tested in accordance with the published specifications.
The instrument has been calibrated by using equipment which has already been calibrated to standards traceable
